Abstract: A combined beam having a desired wavefront is produced from a first electromagnetic beam propagating in a beam direction and a second electromagnetic beam propagating in the beam direction and interfering with the first electromagnetic beam in an interference region. A first power measurement indicates a first combined power of the first electromagnetic beam and the second electromagnetic beam at a first sample point in the interference region. A second power measurement indicates a second combined power of the first electromagnetic beam and the second electromagnetic beam at a second sample point in the interference region. A phase difference between the first electromagnetic beam and the second electromagnetic beam is determined using the first power measurement and the second power measurement. The phase of the first beam can be changed based on the phase difference to produce the combined beam that has the desired wavefront.

Abstract: Optical acquisition systems for direct-to-digital holography are disclosed. The system includes an illumination lens for focusing a reference beam and a beam splitter optically coupled to the illumination lens by the reference beam. A reference mirror is located at a waist of the reference beam and operates to eliminate a reference objective.

Abstract: Coherent transfer of laser energy between laser fields with high efficiency (85-95%) is obtained by energy coupling of nearly copropagating (intersecting) laser beams in mono-atomic vapor and provides an output beam of high power when nearly equal energy pulses are tuned near resonance with the transition of the atom of the vapor (e.g., potassium vapor at 230.degree.-260.degree. C.). The frequencies of the beams differ by approximately the inverse of the excited state lifetime of the atoms for optimum combining (coupling efficiency).